Telemetry is practice of of gathering values at location remote from site of measurement. In the process instrumentation, all the measurements are done remotely since data from one equipment is sent to other equipment for control. The word ‘telemetry’ is coined from Greek terms: tele - remote and metron- measure. In short, telemetry is the science of measuring parameters and collecting data at remote or inaccessible points and transmitting them to receiving equipment for monitoring and taking action from optimum and safe operating point of view.
Telemetry comprises of three steps:
- Converting measured quantity to signal
- Transmission of signal over proper channel
- Re conversion to actual data for analysis and computation
Types of telemetry system
- Landline telemetry system
Power lines, Telephone lines and electrical wires ranging from 50 m-1km. Eg: Current
- Radio-frequency system
Radio links from 1 km to 50km at 4Hz. For distances more than 50 km microwave links are being used 890MHz to 30GHz
Factors affecting telemetry design
- Initial criteria for design and choice is accuracy
- Power levels must be low in order to reduce noise generation
- Selection of apt. bandwidth for data channel and linking to prevent cross talk at receiving ends
- To transmit digital data, detecting errors, recognition capability make system accurate
Objective of Risk assessment for Telemetry design
- Identification of hazards, evaluation and quantification of risks associated with respect to the transfer of monitoring and control functions from existing design to the new Telemetry system as part of installation & commissioning
- Identify and evaluate the hazard and risk due to the interference of Electro Magnetic Interferences and Radio Frequency Interferences to the existing communication equipment on well heads
Study Technique and Data Gathering
- The risk during the transfer of the existing telemetry unit to the modified telemetry unit is assessed. The options which could be considered for safe and easy transfer from the old to the new telemetry system are discussed.
- Meeting and telephonic discussions with the concerned people from Instrumentation, Telecommunication, and Process and HSE departments are scheduled to understand the facility and scope of installation and commissioning of the new RTU in the facility.
Risk assessment associated with transfer of monitoring and control functions
The risk associated with the transfer of telemetry units is mostly towards loss of data from the well heads and the Production station to Onshore. This data is required for reservoir management and for similar logging purposes. The risk to personnel is estimated to be mostly occupational hazards like slips, trips, dropped object etc. and effective safeguards like barricading, signage, proper rigging / lifting procedure is followed to reduce the risk.
Risk assessment methodology
The risk assessment study sequence process is best understood if it is divided into the following steps:
- communicating and analyzing throughout the process establishing the better finding of the solution
- Risk Assessment – an overall process involving risk identifying, risk analysis and risk evaluating
- Risk treatment
- Monitoring and reviewing risks;
- Reporting and recording the results appropriately.
Risk mitigation and tracking
Action plans need to be specified for all risks and the number of action plan may differs from risk to risk based on specifications. However, at any point in time, each task in an action plan has a particular status, such as completed or on-track or considered as non-executable. In either cases risk reduction and residual risk specific to a project at each stage are monitored. A Hazards and Effects register is a useful tool to monitor and track risks, controls and residual risk specific to a project.
Recording and report output
The proceedings of the Risk assessment will be recorded in the specified format of H & E Register. Recommendation (Action /query items) are recorded and the corresponding Risk Assessment Action Sheet are followed up. The report outlines the identification of hazards and to reduce the probability and consequences of an incident that would have a detrimental impact to the personnel, plant, and environment with respect to the with respect to the transfer of monitoring and control functions from existing design to the new Telemetry thus improving efficiencies across widely-dispersed field operations during oil drilling operations and critical infrastructures and also tackling the challenges of maximizing field production and relaying secure, data from remote assets to the corporate enterprise.